Summaries for Patients|1 February 2000

A Case of Cryptococcal Infection in a Patient with an Abnormal Immune System and a Pet Cockatoo

The summary below is from the full report titled “Evidence of Zoonotic Transmission of Cryptococcus neoformans from a Pet Cockatoo to an Immunocompromised Patient.” It is in the 1 February 1999 issue of Annals of Internal Medicine (volume 132, pages 205-208). The authors are J.D. Nosanchuk, S. Shoham, B.C. Fries, D.S. Shapiro, S.M. Levitz, and A. Casadevall.

Summaries for Patients are a service provided by Annals to help patients better understand the complicated and often mystifying language of modern medicine.

Summaries for Patients are presented for informational purposes only. These summaries are not a substitute for advice from your own medical provider. If you have questions about this material, or need medical advice about your own health or situation, please contact your physician. The summaries may be reproduced for not-for-profit educational purposes only. Any other uses must be approved by the American College of Physicians-American Society of Internal Medicine.

What is the problem and what is known about it so far?

Cryptococcus neoformans is a fungus that causes infection in people with abnormal immune systems. Among other things, the immune system helps the body fight off infection. Experts believe that people can become infected with cryptococcus when they breathe in spores of the fungus. Spores can be found in soil and in bird droppings, but nobody had yet described a case where infection was shown to spread directly from a bird to a person.

Why did the researchers do this particular study?

The researchers encountered a case of cryptococcal infection in a woman who was living in the same house as a pet cockatoo. They realized this was an important opportunity to find out whether the patient had acquired her infection from direct exposure to the bird.

Who was studied?

A 72-year-old woman whose immune system was suppressed by medications she was taking after a kidney transplant.

How was the study done?

The researchers collected information about the patient. They isolated cryptococcus from both the patient's body fluids and from the cockatoo's droppings. They then used special laboratory tests to compare the type of cryptococcus from the patient with that from the cockatoo.

What did the researchers find?

The type of cryptococcus in samples from the patient was found to be identical to that in samples from the cockatoo.

What were the limitations of the study?

This is a single case, and the situation described in this case may be unusual. In addition, the presence of the same form of cryptococcus in the patient and the bird suggests but does not absolutely prove that the patient got the infection from the bird. It is possible that both got it from another source or, much less likely, that the bird got it from the patient.

What are the implications of the study?

This case strongly suggests that patients with weakened immune systems can get cryptococcal infection directly from bird droppings by inhaling cryptococcus spores that spread into the air from the droppings. Although this type of situation may be rare, it seems wise to advise persons with abnormal immune systems to avoid pet birds and situations where they might be exposed to large amounts of bird droppings.

Clinical Slide Sets

Terms of Use

The In the Clinic® slide sets are owned and copyrighted by the American College of Physicians (ACP). All text, graphics, trademarks, and other intellectual property incorporated into the slide sets remain the sole and exclusive property of the ACP. The slide sets may be used only by the person who downloads or purchases them and only for the purpose of presenting them during not-for-profit educational activities. Users may incorporate the entire slide set or selected individual slides into their own teaching presentations but may not alter the content of the slides in any way or remove the ACP copyright notice. Users may make print copies for use as hand-outs for the audience the user is personally addressing but may not otherwise reproduce or distribute the slides by any means or media, including but not limited to sending them as e-mail attachments, posting them on Internet or Intranet sites, publishing them in meeting proceedings, or making them available for sale or distribution in any unauthorized form, without the express written permission of the ACP. Unauthorized use of the In the Clinic slide sets will constitute copyright infringement.